Most modern aircraft now use fuel tanks incorporated into the airframe structure and use the wing or fuselage skins, spars and ribs as the boundaries. These boundaries are currently made from rigid structural material such as aluminium alloy or reinforced plastic composite.
U.S. Pat. No. 5,983,945 describes a wing tank liner which limits the amount of fuel that can be spilled in the event of a crash. A neoprene rubber liner is suspended within the fuel tank from a frame or from the tank itself.
It is often necessary to divide up a fuel tank into a number of compartments for aircraft trim, to reduce fuel movements (caused by pitch, roll and yaw) during manoeuvres, and to produce collector cells for the engine fuel feeds. These boundaries are traditionally made from rigid material such as aluminium alloy or of reinforced plastic composites. These traditional materials have a number of advantages such as high tensile strength and stiffness, however their rigidity makes it difficult to remove them for maintenance or tank internal access, particularly within a confined space. They are also relatively dense and thus heavy. For example aluminium alloy typically has a density in the range of 2.85-3.05 Mgm−3, and reinforced plastic composite materials typically have a density in the range of 1.65-1.75 Mgm−3.
It would be desirable to provide a tank which has a lower weight, easier access for inspection and maintenance purposes, and the ability to withstand pressure pulses.